Attachment Faces for Clamped Turbine Stator of a Gas Turbine Engine

ABSTRACT

An airfoil fairing shell for a gas turbine engine includes an airfoil section between an outer vane endwall and an inner vane endwall, at least one of the outer vane endwall and the inner vane endwall including a radial attachment face, a suction side tangential attachment face, a pressure side tangential attachment face, and an axial attachment face.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. patent application Ser. No.14/841,943, filed Sep. 1, 2015, which claims the benefit of U.S. patentapplication Ser. No. 62/047,710, filed Sep. 9, 2014.

BACKGROUND

The present disclosure relates to airfoil components for a gas turbineengine, and more particularly, to attachment faces for a turbine statorwhich itself has an airfoil with endwall platforms and which is radiallycompressed between supporting structural details.

Gas turbine engines, such as those that power modern commercial andmilitary aircraft, generally include a compressor to pressurize anairflow, a combustor to burn a hydrocarbon fuel in the presence of thepressurized air, and a turbine to extract energy from the resultantcombustion gases. The compressor and turbine sections include rotatableblade and stationary vane arrays. The blades and vanes typically includelow and high-pressure airfoils, vanes, vane rings, shrouds, and nozzlesegments.

The stationary vane arrays are typically assembled between outer andinner shrouds, or rings, in a variety of manners. Although the actualelements may vary in their configuration and construction, onesimilarity is that the vanes are typically constructed to allow forthermal expansion. The thermal expansion is typically accommodatedthrough assembly of the vanes relatively loosely in the inner and outershrouds. Although effective, such assembly may result in variousstresses.

SUMMARY

An airfoil fairing shell for a gas turbine engine according to onedisclosed non-limiting embodiment of the present disclosure includes anairfoil section between an outer vane endwall and an inner vane endwall,at least one of the outer vane endwall and the inner vane endwallincluding a radial attachment face, a suction side tangential attachmentface, a pressure side tangential attachment face, and an axialattachment face.

A further embodiment of the present disclosure includes, wherein theradial attachment face, the suction side tangential attachment face, thepressure side tangential attachment face, and the axial attachment faceare formed by a thickened region of at least one of the outer vaneendwall and the inner vane endwall.

A further embodiment of any of the foregoing embodiments of the presentdisclosure includes, wherein the radial attachment face, the suctionside tangential attachment face, the pressure side tangential attachmentface, and the axial attachment face are formed by a thickened region ofthe inner vane endwall.

A further embodiment of any of the foregoing embodiments of the presentdisclosure includes, wherein the suction side tangential attachment faceis parallel to the tangential attachment face.

A further embodiment of any of the foregoing embodiments of the presentdisclosure includes, wherein the suction side tangential attachment faceand the pressure side tangential attachment face are non-parallel to theinner vane endwall.

A further embodiment of any of the foregoing embodiments of the presentdisclosure includes, wherein the suction side tangential attachment faceand the pressure side tangential attachment face are non-parallel.

A further embodiment of any of the foregoing embodiments of the presentdisclosure includes, wherein the suction side tangential attachment faceis generally perpendicular to a resultant aerodynamic load generated bythe airfoil.

A further embodiment of any of the foregoing embodiments of the presentdisclosure includes, wherein the suction side tangential attachment faceis downstream of an aerodynamic center of a resultant aerodynamic loadgenerated by the airfoil.

A further embodiment of any of the foregoing embodiments of the presentdisclosure includes, wherein the suction side tangential attachment faceis aligned with respect to a resultant aerodynamic load generated by theairfoil.

A vane ring for a gas turbine engine according to another disclosednon-limiting embodiment of the present disclosure includes a multiple ofairfoil fairing shells each with a first attachment face formed by athickened region of a vane endwall that forms a mateface, each of themultiple of airfoil fairing shells adjacent to another one of themultiple of airfoil fairing shells at the mateface; and a structuralsupport with a multiple of lugs, each of the multiple of lugs interfaceswith at least one of the first attachment faces of each of the multipleof airfoil fairing shells.

A further embodiment of any of the foregoing embodiments of the presentdisclosure includes, wherein the structural support includes aninterface for attachment to an engine case structure.

A further embodiment of any of the foregoing embodiments of the presentdisclosure includes, wherein the structural support is an arcuatesegment.

A further embodiment of any of the foregoing embodiments of the presentdisclosure includes, wherein the structural support is a full ring.

A further embodiment of any of the foregoing embodiments of the presentdisclosure includes, wherein the lug extends transverse to the matefaceof the vane endwall.

A further embodiment of any of the foregoing embodiments of the presentdisclosure includes, wherein the thickened region of the vane endwallforms a radial attachment face, an axial attachment face, and a pressureside tangential attachment face.

A further embodiment of any of the foregoing embodiments of the presentdisclosure includes, wherein the first attachment face is a suction sidetangential attachment face.

A further embodiment of any of the foregoing embodiments of the presentdisclosure includes, wherein the axial attachment face, the pressureside tangential attachment face, and the suction side tangentialattachment face are generally perpendicular to the radial attachmentface.

A further embodiment of any of the foregoing embodiments of the presentdisclosure includes, wherein the axial attachment face, is generallyperpendicular to the pressure side tangential attachment face and thesuction side tangential attachment face.

A further embodiment of any of the foregoing embodiments of the presentdisclosure includes, wherein the suction side tangential attachment faceis downstream of an aerodynamic center of a resultant aerodynamic loadgenerated by the airfoil fairing shell such that the in plane loading tothe reaction forces on these faces is compressive.

A further embodiment of any of the foregoing embodiments of the presentdisclosure includes, wherein the suction side tangential attachment faceand the axial attachment face are downstream of an aerodynamic center ofa resultant aerodynamic load generated by the airfoil fairing shell suchthat the in plane loading to the reaction forces on these faces iscompressive.

The foregoing features and elements may be combined in variouscombinations without exclusivity, unless expressly indicated otherwise.These features and elements as well as the operation thereof will becomemore apparent in light of the following description and the accompanyingdrawings. It should be understood, however, the following descriptionand drawings are intended to be exemplary in nature and non-limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

Various features will become apparent to those skilled in the art fromthe following detailed description of the disclosed non-limitingembodiment. The drawings that accompany the detailed description can bebriefly described as follows:

FIG. 1 is a schematic cross-section of an example gas turbine enginearchitecture;

FIG. 2 is a schematic cross-section of another example gas turbineengine architecture;

FIG. 3 is an enlarged schematic cross-section of an engine turbinesection;

FIG. 4 is an enlarged schematic cross-section of an engine turbinesection airfoil fairing shell according to one disclosed non-limitingembodiment;

FIG. 5 is a perspective view of turbine vane ring;

FIG. 6 is an enlarged perspective partial phantom view of the turbinevane ring;

FIG. 7 is a top partial phantom view of an airfoil fairing shellaccording to another disclosed non-limiting embodiment;

FIG. 8 is a top partial phantom view of an airfoil fairing shellaccording to another disclosed non-limiting embodiment;

FIG. 9 is a top partial phantom view of an airfoil fairing shellaccording to another disclosed non-limiting embodiment;

FIG. 10 is a top partial phantom view of an airfoil fairing shellaccording to another disclosed non-limiting embodiment; and

FIG. 11 is a top partial phantom view of an airfoil fairing shellaccording to another disclosed non-limiting embodiment.

DETAILED DESCRIPTION

FIG. 1 schematically illustrates a gas turbine engine 20. The gasturbine engine 20 is disclosed herein as a two-spool turbo fan thatgenerally incorporates a fan section 22, a compressor section 24, acombustor section 26, and a turbine section 28. Alternative enginearchitectures 200 might include an augmentor section 12, an exhaust ductsection 14, and a nozzle section 16 (FIG. 2) among other systems orfeatures. The fan section 22 drives air along a bypass flowpath and intothe compressor section 24 to drive core air along a core flowpath. Thecore air is compressed then communicated into the combustor section 26for downstream expansion through the turbine section 28. Althoughdepicted as a turbofan in the disclosed non-limiting embodiment, itshould be appreciated that the concepts described herein are notlimited, only to turbofans as the teachings may be applied to othertypes of turbine engine architectures such as turbojets, turboshafts,and three-spool (plus fan) turbofans.

The engine 20 generally includes a low spool 30 and a high spool 32mounted for rotation about an engine central longitudinal axis Arelative to an engine case structure 36 via several bearing compartments38. The low spool 30 generally includes an inner shaft 40 thatinterconnects a fan 42, a low pressure compressor (“LPC”) 44 and a lowpressure turbine (“LPT”) 46. The inner shaft 40 drives the fan 42directly or through a geared architecture 48 to drive the fan 42 at alower speed than the low spool 30. An exemplary reduction transmissionis an epicyclic transmission, namely a planetary or star gear system.

The high spool 32 includes an outer shaft 50 that interconnects a highpressure compressor (“HPC”) 52 a and high pressure turbine (“HPT”) 54. Acombustor 56 is arranged between the HPC 52 and the HPT 54. Core airflowis compressed by the LPC 44, then the HPC 52, mixed with the fuel andburned in the combustor 56, then expanded over the HPT 54 and the LPT 46which rotationally drive the respective low spool 30 and high spool 32in response to the expansion.

With reference to FIG. 3, an enlarged schematic view of a portion of theHPT 54 is shown by way of example; however, other engine sections willalso benefit herefrom. A shroud assembly 60 mounted to the engine casestructure 36 supports a Blade Outer Air Seal (BOAS) assembly 62 with amultiple of circumferentially distributed BOAS 64 proximate to a rotorassembly 66 (one schematically shown).

The shroud assembly 60 and the BOAS assembly 62 are axially disposedbetween a forward stationary vane ring 68 and an aft stationary vanering 70. The rotor assembly 66 includes an array of blades 84circumferentially disposed around a disk 86. Each blade 84 includes aroot 88, a platform 90, and an airfoil 92. The blade roots 88 arereceived within a rim 94 of the disk 86 and the airfoils 92 extendradially outward such that a tip 96 of each airfoil 92 adjacent to theblade outer air seal (BOAS) assembly 62. The platform 90 separates a gaspath side inclusive of the airfoil 92 and a non-gas path side inclusiveof the root 88.

With reference to FIG. 4, the forward stationary vane ring 68 will bedescribed as a clamped stator assembly, however, it should beappreciated that the aft stationary vane ring 70 as well as other vanerings in the turbine section and the compressor section will alsobenefit herefrom. In the example forward stationary vane ring 68, eachairfoil 72 extends between a respective inner vane endwall 76 and anouter vane endwall 80 to form an airfoil fairing shell 106. Each airfoilfairing shell 106 is respectively clamped between an outer structuralsupport 110, and an inner structural support 112 (also shown in FIG. 5).

The outer structural support 110, and the inner structural support 112may be full rings or circumferentially segmented structures that aremounted within or a portion of the engine case structure 36, or attachedthereto via fasteners, clamping, pins, or other such interface 114, 116(illustrated schematically). That is, the airfoil fairing shells 106 areclamped into a full ring or circumferentially segmented outer and innerstructural support 110, 112 that are, in turn, formed, fastened orotherwise located in the engine case structure 36 (FIG. 3). In theexample circumferentially segmented structure, each segment of the outerstructural support 110 and/or the inner structural support 112 maysupport a cluster of one or more airfoil fairing shells 106 (three shownin FIG. 6).

With reference to FIG. 7, each airfoil 72 defines a blade chord betweena leading edge 120, which may include various forward and/or aft sweepconfigurations, and a trailing edge 122. A first airfoil sidewall 124that may be convex to define a suction side, and a second airfoilsidewall 126 that may be concave to define a pressure side, are joinedat the leading edge 120 and at the axially spaced trailing edge 122. Anaerodynamic center “C” of the airfoil is located at about a quarterchord position, however, such aerodynamic centers may vary dependentupon the airfoil.

The inner vane endwall 76 and the outer vane endwall 80 are generally aparallelogram, chevron, arc, or other shape when viewed from the top andgenerally includes a respective forward edge 130, 132, an aft edge 134,136 and a mateface 138A, 138B, 140A, 140B therebetween. The endwalls 70,80 may be cylindrical, conical, arbitrary axisymmetric, ornon-axisymmetric when viewed in cross-section. The non-gaspath face ofthe platform may be any of these as well. That is, the airfoil 72, theinner vane endwall 76, and the outer vane endwall 80 form the airfoilfairing shell 106 that is radially clamped by the outer structuralsupport 110, and the inner structural support 112.

The airfoil fairing shell 106 may include passages “P” (three shown) forcooling airflow and or electrical conduits, may be solid, may be hollow,or combinations thereof. Such an arrangement facilitates manufacture ofmetallic or non-metallic airfoil fairing shells, particularly but notexclusively those of low-ductility and/or low coefficient of thermalexpansion materials, that are readily assembled to the outer structuralsupport and the inner structural support which, in turn, aremanufactured of metallic or non-metallic material and which may bemanufactured from the same material as or dissimilar material to theairfoil fairing shells.

In this disclosed non-limiting embodiment, the outer vane endwall 80will be described, however, it should be appreciated that the inner vaneendwall 76 as well as other vane rings will also benefit herefrom. Theouter vane endwall 80 generally includes a radial attachment face 150, asuction side tangential attachment face 152, a pressure side tangentialattachment face 154, and an axial attachment face 156. The attachmentfaces 150, 152, 154, 156 transmit axial and tangential aerodynamic loadsfrom the airfoil fairing shell 106 into the structural supports andtransmit clamping load through the fairing shell.

The airfoil fairing shell 106 include cylindrical, conical, arbitraryaxisymmetric or planar radial attachment faces through which thespanwise clamping load is generally transmitted, and two pairs oforthogonal planar attachment faces through which aerodynamic loads andretention loads are generally transmitted, and which arequasi-orthogonal to the radial direction at the airfoil'scircumferential station. It should be appreciated that one attachmentface may be the primary attachment face while another attachment face isa secondary attachment face with respect configurations where the facesare rotated with respect to the engine axis. Axial and tangentialoriented primary and secondary attachment faces are one disclosednon-limiting embodiment. More generally, primary and secondaryattachment faces, where axial and tangentially aligned are one specifictype, where primary aligned with the resultant load is another specifictype, and where primary aligned with the platform mateface edge is athird type. The primary and secondary are orthogonal to one another, andare quasi-orthogonal to the radial direction at the airfoil'scircumferential station.

The attachment faces 150, 152, 154, 156 are generally formed bythickened areas of the outer vane endwall 80 or other features such astabs that are arranged to form these faces and interface with respectiveattachment faces formed by the associated outer structural support 110(FIG. 6). In this disclosed non-limiting embodiment, the outerstructural support 110 includes a series of lugs 160 provide tangentialreaction faces that may be angled with respect to the engine axis A andextend transverse to a respective circumferential interface 170 betweeneach airfoil fairing shell 106 (FIG. 6, 9, 10). Alternatively, theseries of lugs 160 provide tangential reaction faces is parallel to theengine axis (FIG. 7).

The attachment faces 150, 152, 154, 156 are arranged to transmit loadsbetween the respective structural supports 110, 112 and the airfoilfairing shell 106. The surface of the thickened area of the airfoilfairing shell 106 forms the radial attachment face 150 that is clampedbetween the outer and inner structural support 110, 112.

The attachment faces 152, 154, 156 react in-plane loads formed by thestep transitions of the thickened areas of the outer vane endwall 80.The attachment faces 152, 154, 156 may be aligned with the axial andtangential directions or rotated to an arbitrary angle, such as thatwhich presents a large face perpendicular to the resultant aerodynamicload (FIG. 9). The suction side tangential attachment face 152 is taskedwith reacting aerodynamic in-plane loads and may be located downstream,and to the suction side of the aerodynamic center “C” of the airfoilsuch that aerodynamic loads tend to create compressive rather thantensile loads in the material that are in the plane with the platformbetween the aerodynamic center “C” to the attachment faces. That is, thesuction side tangential attachment face 152 interfaces with one of theseries of lugs 160 of the structural support 110 to provide a primaryreaction load. The axial attachment face 156 also interfaces with thestructural support 110 to provide a secondary reaction load.

In this disclosed non-limiting embodiment, the primary reaction load andthe secondary reaction load are non-parallel to the resultantaerodynamic load from the aerodynamic center “C” as generated by theairfoil 72, and the suction side tangential attachment face 152 isnon-parallel to the matefaces 138A, 138B. Here, the suction sidetangential attachment face 152 and the pressure side tangentialattachment face 154 are perpendicular to the forward edge 130 and theaft edge 134. In this disclosed non-limiting embodiment, a corner 180 atthe interface between the suction side tangential attachment face 152and the axial attachment face 156 is chamfered. The chamfered corner180. The purpose of such a chamfer allows the load bearing faces on thestator shell to clear the edges of the complementary faces' fillet attheir junction on the structural platform to prevent contact stressconcentration (FIG. 11).

In another disclosed non-limiting embodiment, the primary reaction loadis parallel to a resultant aerodynamic load from an aerodynamic centeras generated by the airfoil and the suction side tangential attachmentface 152 is non-parallel to the matefaces 138A, 138B (FIG. 9). Notably,the primary and secondary load transmitting faces (alternatively calledthe axial and tangential faces when these faces are not angled withrespect to the engine axis) are always perpendicular to each other,regardless of whether or not one of them is aligned to the resultantloading direction.

In another disclosed non-limiting embodiment, the suction sidetangential attachment face 152 and the pressure side tangentialattachment face 154 are generally parallel to the matefaces 138A, 138Bof the outer vane endwall 80 (FIG. 10). Such arrangements may facilitateassembly into the engine 20.

The attachment faces 150, 152, 154, 156 enable the use of separatestructural platforms for a turbine stator which itself has an airfoiland endwalls while limiting tensile stresses in the plane of theplatform.

The use of the terms “a,” “an,” “the,” and similar references in thecontext of description (especially in the context of the followingclaims) are to be construed to cover both the singular and the plural,unless otherwise indicated herein or specifically contradicted bycontext. The modifier “about” used in connection with a quantity isinclusive of the stated value and has the meaning dictated by thecontext (e.g., it includes the degree of error associated withmeasurement of the particular quantity). All ranges disclosed herein areinclusive of the endpoints, and the endpoints are independentlycombinable with each other.

Although the different non-limiting embodiments have specificillustrated components, the embodiments of this invention are notlimited to those particular combinations. It is possible to use some ofthe components or features from any of the non-limiting embodiments incombination with features or components from any of the othernon-limiting embodiments.

It should be appreciated that like reference numerals identifycorresponding or similar elements throughout the several drawings. Itshould also be appreciated that although a particular componentarrangement is disclosed in the illustrated embodiment, otherarrangements will benefit herefrom.

Although particular step sequences are shown, described, and claimed, itshould be understood that steps may be performed in any order, separatedor combined unless otherwise indicated and will still benefit from thepresent disclosure.

The foregoing description is exemplary rather than defined by thelimitations within. Various non-limiting embodiments are disclosedherein, however, one of ordinary skill in the art would recognize thatvarious modifications and variations in light of the above teachingswill fall within the scope of the appended claims. It is therefore to beunderstood that within the scope of the appended claims, the disclosuremay be practiced other than as specifically described. For that reasonthe appended claims should be studied to determine true scope andcontent.

1. An airfoil fairing shell for a gas turbine engine comprising: anairfoil section between an outer vane endwall and an inner vane endwall,at least one of said outer vane endwall and said inner vane endwallincluding a radial attachment face, a suction side tangential attachmentface, a pressure side tangential attachment face, and an axialattachment face, said suction side tangential attachment face transverseto a resultant aerodynamic load generated by said airfoil.
 2. Theairfoil fairing shell as recited in claim 1, wherein said radialattachment face, said suction side tangential attachment face, saidpressure side tangential attachment face, and said axial attachment faceare formed by a thickened region of at least one of said outer vaneendwall and said inner vane endwall.
 3. The airfoil fairing shell asrecited in claim 1, wherein said radial attachment face, said suctionside tangential attachment face, said pressure side tangentialattachment face, and said axial attachment face are formed by athickened region of said inner vane endwall.
 4. The airfoil fairingshell as recited in claim 1, wherein said suction side tangentialattachment face is parallel to said pressure side tangential attachmentface.
 5. The airfoil fairing shell as recited in claim 1, wherein saidsuction side tangential attachment face and said pressure sidetangential attachment face are non-parallel to said inner vane endwall.6. The airfoil fairing shell as recited in claim 1, wherein said suctionside tangential attachment face and said pressure side tangentialattachment face are non-parallel to an edge of said outer vane endwall.7. (canceled)
 8. The airfoil fairing shell as recited in claim 1,wherein said suction side tangential attachment face is downstream of anaerodynamic center of a resultant aerodynamic load generated by saidairfoil.
 9. (canceled)
 10. A vane ring for a gas turbine engine,comprising: a multiple of airfoil fairing shells each with a firstattachment face formed by a thickened region of a vane endwall thatforms a mateface, each of said multiple of airfoil fairing shellsadjacent to another one of said multiple of airfoil fairing shells atsaid mateface; and a structural support with a multiple of lugs, each ofsaid multiple of lugs interfaces with at least one of said firstattachment faces of each of said multiple of airfoil fairing shells. 11.The vane ring as recited in claim 10, wherein said structural supportincludes an interface for attachment to an engine case structure. 12.The vane ring as recited in claim 10, wherein said structural support isan arcuate segment.
 13. The vane ring as recited in claim 10, whereinsaid structural support is a full ring.
 14. The vane ring as recited inclaim 10, wherein said lug extends transverse to said mateface of saidvane endwall.
 15. The vane ring as recited in claim 10, wherein saidthickened region of said vane endwall forms a radial attachment face, anaxial attachment face, and a pressure side tangential attachment face.16. The vane ring as recited in claim 15, wherein said first attachmentface is a suction side tangential attachment face.
 17. The vane ring asrecited in claim 16, wherein said axial attachment face, said pressureside tangential attachment face, and said suction side tangentialattachment face are transverse to said radial attachment face.
 18. Thevane ring as recited in claim 17, wherein said axial attachment face istransverse to said pressure side tangential attachment face and saidsuction side tangential attachment face.
 19. The vane ring as recited inclaim 18, wherein said suction side tangential attachment face isdownstream of an aerodynamic center of a resultant aerodynamic loadgenerated by said airfoil fairing shell such that the in plane loadingto the reaction forces on these faces is compressive.
 20. The vane ringas recited in claim 18, wherein said suction side tangential attachmentface and said axial attachment face are downstream of an aerodynamiccenter of a resultant aerodynamic load generated by said airfoil fairingshell such that the in plane loading to the reaction forces on thesefaces is compressive.